Armstrong Educational Handbook and All Products Catalog

North America La tin America Indi a Europe / Middle East / Africa Chi na Pa cifi c Rimarmstronginternational.com

For more than 100 years, Armstrong has been providing utility system solutions and optimization for our global partners through products, education, training aids and service. Because we know our customers are always looking for ways to make their facilities more ef cient, we offer total system solutions for steam, air and hot water.

In addition to energy- and cost-saving products, Armstrong provides comprehensive services. We offer turn-key installation, operation and maintenance services; steam and compressed air system audits; steam trap management; process drying optimization; condensate system improvement; insect heat treatment; and hot-water solutions for process, safety, sanitation and domestic applicationsall of which can be customized to help improve your bottom line.

Customers have been turning to Armstrong for more than 100 years because of a continuing need to optimize the ef ciency of their industrial, institutional and commercial facilities. It is our intelligence and experience that separate us from other companies.

Were proud of the tradition weve established at Armstrongmerging energy and environment while sharing our vast knowledge, so future generations can bene t from a healthier, cleaner world.

Armstrong offers the following utility system and service solutions: Steam and Condensate Solutions Steam trapping and steam tracing

equipment, testing and monitoring, strainers, air vents, liquid drainers, and condensate recovery equipment

Hot Water Solutions Hot water heaters, balancing valves, radiator products, mixing valves and hose stations

Heat Transfer Solutions Heating and cooling coils, unit heaters, and tank heaters

Humidi cation Solutions Conditioned steam humidi ers, gas red humidi ers, electric steam humidi ers and fogging systems

Pressure/Temperature Control Solutions Pressure reducing valves and temperature regulators

Armstrong Service Solutions Armstrong Service offers complete utility system optimization services for industrial, institutional and commercial facilities worldwide. We provide steam system audits and utility system performance evaluations; long-term operation and maintenance to ensure best-in-class performance; turn-key sustaining engineering that includes installation and continuing engineering solutions; utility optimization, which allows us to identify energy-saving projects within your utility system; and utility monetization, whereby we purchase your utility assets to free up cash for use elsewhere in your organization.

North America La tin America I ndia Europe / Middle East / Africa Chi na Pa cifi c Rimarmstronginternational.com

2011 Armstrong International, Inc. Designs, materials, and performance ratings are subject to change without notice.

1North America La tin America Indi a Europe / Middle East / Africa Chi na Pa cifi c Rim

armstronginternational.com

Book Page Numbers

Tab Guide

Steam Trapping and Steam Tracing Equipment (Pages 63 thru 183 )

Steam Trap Management Products & Services (Pages 186 thru 197 )

Condensate Recovery Equipment (Pages 200 thru 259 )

Pressure and Temperature Controls (Pages 262 thru 333 )

Heating and Cooling Coils (Pages 336 thru 405 )

Radiator Products (Pages 408 thru 417 )

Strainers (Pages 420 thru 437 )

Air Vents (Pages 440 thru 459 )

Liquid Drainers (Pages 462 thru 515 )

Hot Water Solutions (Pages 518 thru 541 )

Ancillary Products (Pages 544 thru 551 )

Service, Training and Warranties (Pages 554 thru 576)

2North America La tin America I ndia Europe / Middle East / Africa Chi na Pa cifi c Rim


Engineering GuidelinesSteam Conservation Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 thru 61Draining Liquids From Compressed Air & Other Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466 thru 491

Steam Trapping and Steam Tracing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 thru 183Steam Trap ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Inverted Bucket Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70Automatic Differential Condensate Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110Float & Thermostatic Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118Trap Valve Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138Universal Stainless Steel Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150Controlled Disc Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152Thermostatic Wafer Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158Super Heat Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162Bimetallic Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162Thermostatic Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168Radiator Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171Clean Steam Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172Steam Tracing Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174Steam Distribution Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176Condensate Collection Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178Steam Trap Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Steam Trap Management Products and Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185SteamEye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186SteamStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186

Condensate Recovery Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 thru 258Pumping Trap ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202Pumping Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204Double Duty Steam Trap/Pump Combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220Pumping Trap Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227Rescue Cap Non-Electric Steam/Air Powered Pump Retro t Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232Electric Condensate Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234Flash Recovery Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

Pressure and Temperature Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 thru 333Pressure and Temperature Control ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Direct Acting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 Posi-Pressure Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

Internally Piloted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 Externally Piloted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289Temperature Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303Control Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314Piston Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332

Table of Contents Book Page No.



Book Page No.

Table of Contents

Heating and Cooling Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 thru 404Heavy Duty Finned Tube Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336Steam Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343Liquid Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353Boiler Air Preheating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360Plate Fin Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364Unit Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370Door Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378Hot Breath Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388Hot Bin Heaters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388Steam Condenser Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389Duramix Heating Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390Tank Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396

Radiator Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 thru 417Radiator ID Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408Thermostatic Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410Thermostatic Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412Radiator Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414Radiator Trap Replacement Capsules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415

Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420 thru 436Strainer ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422

Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440 thru 459Air Vent ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442

Liquid Drainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462 thru 514Liquid Drainer ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463

Hot Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518 thru 541Hot Water Solutions ID Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518Flo-Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524Hose Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536

Ancillary Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544 thru 550Drain Separators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544Sump Ejector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546Condensate Coolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548Noiseless Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549Exhaust Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550

4North America La tin America I ndia Europe / Middle East / Africa Chi na Pa cifi c Rim


Service, Training and Warranties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554 thru 572Armstrong Service, Inc. (ASI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 554Armstrong University - Global Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555Training Aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556Web Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 558Videotapes/DVDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 560Warranties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562Sign-Up Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565Armstrong Facility Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566Armstrong Model Number Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567Armstrong Product Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572

Steam SystemsTraps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Temperature Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303Thermostatic Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440Coils Heavy Duty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 Light Duty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 Tank Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 Face and By-pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390Flash Recovery Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253Instantaneous Water Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518Thermostatic Mixing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536Washdown Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Radiator Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408Steam Distribution Manifolds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176Unit Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370Steam Trap Testing and Monitoring Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

Condensate Recovery SystemsPumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200Flash Recovery Vessels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253Posi-Pressure Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283Condensate Collection Manifolds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

Compressed Air SystemsLiquid Drainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262

Table of Contents by System Book Page No.



Process Air HeatingCoils (Heavy Duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Temperature Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Thermostatic Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410

Hot Water SystemsFlo-Direct Direct Contact Gas-Fired Water Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524Instantaneous Water Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518Instantaneous Water Heater Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518Shell & Tube Heat Exchangers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518Steam and Water Mixing Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536Washdown Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537Radiator Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 440Coils (Light Duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364Noiseless Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Temperature Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Hose Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536

HVAC SystemsCoils (Light Duty) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364Coils (Face and By-pass) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Pressure Reducing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Temperature Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303Thermostatic Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Radiator Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408Posi-Pressure Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283Condensate Coolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 548

Hydronic/Radiant SystemsRadiator Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412Thermostatic Mixing Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520Instantaneous Water Heater Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519Liquid Drainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462Strainers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Temperature Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

Table of Contents by System Book Page No.

6North America Latin America India Europe / Middle East / Africa China Pacifi c Rim


Designs, materials, weights and performance ratings are approximate and subject to change without notice. Visit www.armstronginternational.com for up-to-date information.

Say energy. Think environment. And vice versa.Any company that is energy conscious is also environmentally conscious. Less energy consumed means less waste, fewer emissions and a healthier environment.

In short, bringing energy and environment together lowers the cost industry must pay for both. By helping companies manage energy, Armstrong products and services are also helping to protect the environment.

Armstrong has been sharing know-how since we invented the energy-effi cient inverted bucket steam trap in 1911. In the years since, customers savings have proven again and again that knowledge not shared is energy wasted.

Armstrongs developments and improvements in steam trap design and function have led to countless savings in energy, time and money. This section has grown out of our decades of sharing and expanding what weve learned. It deals with the operating principles of steam traps and outlines their specifi c applications to a wide variety of products and industries. Youll fi nd it a useful complement to other Armstrong litera-ture and the Armstrong Steam-A-ware software program for sizing and selecting steam traps, pressure reducing valves and water heaters, which can be requested through Armstrongs Web site, armstronginternational.com.

This section also includes Recommendation Charts that summarize our fi ndings on which type of trap will give optimum performance in a given situation and why.

IMPORTANT: This section is intended to summarize general principles of installation and operation of steam traps, as outlined above. Actual installation and operation of steam trapping equipment should be performed only by experienced personnel. Selection or installation should always be accompanied by competent technical assistance or advice. This data should never be used as a substitute for such technical advice or assistance. We encourage you to contact Armstrong or its local representative for further details.

Bringing Energy Down to Earth

CG-1




A quick reference Recommendation Chart appears throughout the HOW TO TRAP sections of this catalog, pages CG-17 to CG-43.

A feature code system (ranging from A to Q) supplies you with at-a-glance information.

The chart covers the type of steam traps and the major advantages that Armstrong feels are superior for each particular application.

For example, assume you are looking for information concerning the proper trap to use on a gravity drained jacketed kettle. You would:

1. Turn to the How to Trap Jacketed Kettles section, pages CG-35 to CG-36, and look in the lower right-hand corner of page CG-35. The Recommendation Chart located there is reprinted below for your convenience. (Each section has a Recommendation Chart.)

2. Find Jacketed Kettles, Gravity Drain in the fi rst column under Equipment Being Trapped and read to the right for Armstrongs 1st Choice and Feature Code. In this case, the fi rst choice is an IBLV and the feature code letters B, C, E, K, N are listed.

3. Now refer to Chart CG-2 below, titled How Various Types of Steam Traps Meet Specifi c Operating Requirements and read down the extreme left-hand column to each of the letters B, C, E, K, N. The letter B, for example, refers to the traps ability to provide energy-conserving operation.

4. Follow the line for B to the right until you reach the column that corresponds to our fi rst choice, in this case the inverted bucket. Based on tests and actual operating conditions, the energy-conserving performance of the inverted bucket steam trap has been rated Excellent. Follow this same procedure for the remaining letters.

Abbreviations IB Inverted Bucket Trap IBLV Inverted Bucket Large Vent BM Bimetallic Trap F&T Float and Thermostatic Trap CD Controlled Disc Trap DC Automatic Differential Condensate Controller CV Check Valve T Thermic Bucket PRV Pressure Reducing Valve

Instructions for Using the Recommendation Charts

Chart CG-1. Recommendation Chart (See chart below for Feature Code References.)

Equipment Being Trapped 1st Choice and Feature Code Alternate Choice

Jacketed Kettles Gravity Drain

IBLV B, C, E, K, N F&T or Thermostatic

Jacketed Kettles Syphon Drain

DC B, C, E, G, H, K, N, P IBLV

Chart CG-2. How Various Types of Steam Traps Meet Specific Operating Requirements Feature

Code Characteristic IB BM F&T Disc Thermostatic DC

A Method of Operation (1) Intermittent (2) Intermittent Continuous Intermittent (2) Intermittent ContinuousB Energy Conservation (Time in Service) Excellent Excellent Good Poor Fair (3) ExcellentC Resistance to Wear Excellent Excellent Good Poor Fair ExcellentD Corrosion Resistance Excellent Excellent Good Excellent Good ExcellentE Resistance to Hydraulic Shock Excellent Excellent Poor Excellent (4) Poor ExcellentF Vents Air and CO2 at Steam Temperature Yes No No No No YesG Ability to Vent Air at Very Low Pressure (1/4 psig) Poor (5) NR Excellent (5) NR Good ExcellentH Ability to Handle Start-Up Air Loads Fair Excellent Excellent Poor Excellent ExcellentI Operation Against Back Pressure Excellent Excellent Excellent Poor Excellent ExcellentJ Resistance to Damage From Freezing (6) Good Good Poor Good Good GoodK Ability to Purge System Excellent Good Fair Excellent Good ExcellentL Performance on Very Light Loads Excellent Excellent Excellent Poor Excellent ExcellentM Responsiveness to Slugs of Condensate Immediate Delayed Immediate Delayed Delayed ImmediateN Ability to Handle Dirt Excellent Fair Poor Poor Fair ExcellentO Comparative Physical Size (7) Large Small Large Small Small LargeP Ability to HandleFlash Steam Fair Poor Poor Poor Poor ExcellentQ Mechanical Failure (Open or Closed) Open Open Closed (8) Open (9) Open

(1) Drainage of condensate is continuous. Discharge is intermittent. (2) Can be continuous on low load. (3) Excellent when secondary steam is utilized. (4) Bimetallic and wafer traps good. (5) Not recommended for low pressure operations.

(6) Cast iron traps not recommended.(7) In welded stainless steel construction medium.(8) Can fail closed due to dirt.(9) Can fail either open or closed, depending upon the design of the

bellows.

CG-2




What They AreHow to Use ThemThe heat quantities and temperature/pressure relationships referred to in this section are taken from the Properties of Saturated Steam table.

Definitions of Terms UsedSaturated Steam is pure steam at the temperature that corresponds to the boiling temperature of water at the existing pressure.

Absolute and Gauge Pressures Absolute pressure is pressure in pounds per square inch (psia) above a perfect vacuum. Gauge pressure is pressure in pounds per square inch above atmospheric pressure, which is 14.7 pounds per square inch absolute. Gauge pressure (psig) plus 14.7 equals absolute pressure. Or, absolute pressure minus 14.7 equals gauge pressure.

Pressure/Temperature Relationship (Columns 1, 2 and 3). For every pressure of pure steam there is a corresponding temperature. Example: The temperature of 250 psig pure steam is always 406F.

Heat of Saturated Liquid (Column 4). This is the amount of heat required to raise the temperature of a pound of water from 32F to the boiling point at the pressure and temperature shown. It is expressed in British thermal units (Btu).

Latent Heat or Heat of Vaporization (Column 5). The amount of heat (expressed in Btu) required to change a pound of boiling water to a pound of steam. This same amount of heat is released when a pound of steam is condensed back into a pound of water. This heat quantity is different for every pressure/temperature combination, as shown in the steam table.

Total Heat of Steam (Column 6). The sum of the Heat of the Liquid (Column 4) and Latent Heat (Column 5) in Btu. It is the total heat in steam above 32F.

Specifi c Volume of Liquid (Column 7). The volume per unit of mass in cubic feet per pound.

Specifi c Volume of Steam (Column 8). The volume per unit of mass in cubic feet per pound.

How the Table Is UsedIn addition to determining pressure/temperature relationships, you can compute the amount of steam that will be condensed by any heating unit of known Btu output. Conversely, the

table can be used to determine Btu output if steam condensing rate is known. In the application portion of this section, there are several references to the use of the steam table.

Steam Tables

Table CG-1. Properties of Saturated Steam (Abstracted from Keenan and Keyes, THERMODYNAMIC PROPERTIES OF STEAM, by permission of John Wiley & Sons, Inc.)

Col. 1 Gauge

Pressure

Col. 2 Absolute Pressure

(psia)

Col. 3 Steam Temp.

(F)

Col. 4 Heat of

Sat. Liquid (Btu/lb)

Col. 5 Latent Heat

(Btu/lb)

Col. 6 Total Heat of Steam (Btu/lb)

Col. 7 Specific

Volume of Sat. Liquid

(cu ft/lb)

Col. 8 Specific

Volume of Sat. Steam

(cu ft/lb)In

ches

of V

acuu

m29.743 0.08854 32.00 0.00 1075.8 1075.8 0.016022 3306.0029.515 0.2 53.14 21.21 1063.8 1085.0 0.016027 1526.0027.886 1.0 101.74 69.70 1036.3 1106.0 0.016136 333.6019.742 5.0 162.24 130.13 1001.0 1131.0 0.016407 73.529.562 10.0 193.21 161.17 982.1 1143.3 0.016590 38.427.536 11.0 197.75 165.73 979.3 1145.0 0.016620 35.145.490 12.0 201.96 169.96 976.6 1146.6 0.016647 32.403.454 13.0 205.88 173.91 974.2 1148.1 0.016674 30.061.418 14.0 209.56 177.61 971.9 1149.5 0.016699 28.04

PSIG

0.0 14.696 212.00 180.07 970.3 1150.4 0.016715 26.801.3 16.0 216.32 184.42 967.6 1152.0 0.016746 24.752.3 17.0 219.44 187.56 965.5 1153.1 0.016768 23.395.3 20.0 227.96 196.16 960.1 1156.3 0.016830 20.0910.3 25.0 240.07 208.42 952.1 1160.6 0.016922 16.3015.3 30.0 250.33 218.82 945.3 1164.1 0.017004 13.7520.3 35.0 259.28 227.91 939.2 1167.1 0.017078 11.9025.3 40.0 267.25 236.03 933.7 1169.7 0.017146 10.5030.3 45.0 274.44 243.36 928.6 1172.0 0.017209 9.4040.3 55.0 287.07 256.30 919.6 1175.9 0.017325 7.7950.3 65.0 297.97 267.50 911.6 1179.1 0.017429 6.6660.3 75.0 307.60 277.43 904.5 1181.9 0.017524 5.8270.3 85.0 316.25 286.39 897.8 1184.2 0.017613 5.1780.3 95.0 324.12 294.56 891.7 1186.2 0.017696 4.6590.3 105.0 331.36 302.10 886.0 1188.1 0.017775 4.23100.0 114.7 337.90 308.80 880.0 1188.8 0.017850 3.88110.3 125.0 344.33 315.68 875.4 1191.1 0.017922 3.59120.3 135.0 350.21 321.85 870.6 1192.4 0.017991 3.33125.3 140.0 353.02 324.82 868.2 1193.0 0.018024 3.22130.3 145.0 355.76 327.70 865.8 1193.5 0.018057 3.11140.3 155.0 360.50 333.24 861.3 1194.6 0.018121 2.92150.3 165.0 365.99 338.53 857.1 1195.6 0.018183 2.75160.3 175.0 370.75 343.57 852.8 1196.5 0.018244 2.60180.3 195.0 379.67 353.10 844.9 1198.0 0.018360 2.34200.3 215.0 387.89 361.91 837.4 1199.3 0.018470 2.13225.3 240.0 397.37 372.12 828.5 1200.6 0.018602 1.92250.3 265.0 406.11 381.60 820.1 1201.7 0.018728 1.74

300.0 417.33 393.84 809.0 1202.8 0.018896 1.54400.0 444.59 424.00 780.5 1204.5 0.019340 1.16450.0 456.28 437.20 767.4 1204.6 0.019547 1.03500.0 467.01 449.40 755.0 1204.4 0.019748 0.93600.0 486.21 471.60 731.6 1203.2 0.02013 0.77900.0 531.98 526.60 668.8 1195.4 0.02123 0.50

1200.0 567.22 571.70 611.7 1183.4 0.02232 0.361500.0 596.23 611.60 556.3 1167.9 0.02346 0.281700.0 613.15 636.30 519.6 1155.9 0.02428 0.242000.0 635.82 671.70 463.4 1135.1 0.02565 0.192500.0 668.13 730.60 360.5 1091.1 0.02860 0.132700.0 679.55 756.20 312.1 1068.3 0.03027 0.113206.2 705.40 902.70 0.0 902.7 0.05053 0.05

CG-3




Flash Steam (Secondary)What is fl ash steam? When hot condensate or boiler water, under pressure, is released to a lower pressure, part of it is re-evaporated, becoming what is known as fl ash steam.

Why is it important? This fl ash steam is important because it contains heat units that can be used for economical plant operationand which are otherwise wasted.

How is it formed? When water is heated at atmospheric pressure, its temperature rises until it reaches 212F, the highest temperature at which water can exist at this pressure. Additional heat does not raise the temperature, but converts the water to steam.

The heat absorbed by the water in raising its temperature to boiling point is called sensible heat or heat of saturated liquid. The heat required to convert water at boiling point to steam at the same temperature is called latent heat. The unit of heat in common use is the Btu, which is the amount of heat required to raise the temperature of one pound of water 1F at atmospheric pressure.

If water is heated under pressure, however, the boiling point is higher than 212F, so the sensible heat required is greater. The higher the pressure, the higher the boiling temperature and the higher the heat content. If pressure is reduced, a certain amount of sensible heat is released. This excess heat will be absorbed in the form of latent heat, causing part of the water to fl ash into steam.

Condensate at steam temperature and under 100 psig pressure has a heat content of 308.8 Btu per pound. (See Column 4 in Steam Table.) If this condensate is discharged to atmospheric pressure (0 psig), its heat content instantly drops to 180 Btu per pound. The surplus of 128.8 Btu re-evaporates or fl ashes a portion of the condensate. The percentage that will fl ash to steam can be computed using the formula:

% fl ash steam = x 100 SH = Sensible heat in the condensate at the higher pressure before discharge.SL = Sensible heat in the condensate at the lower pressure to which discharge takes place.H = Latent heat in the steam at the lower pressure to which the condensate has been discharged.

% fl ash steam = x 100 =13.3%

Chart CG-3 shows the amount of secondary steam that will be formed when discharging condensate to different pressures. Other useful tables will be found on page CG-53 (Useful Engineering Tables).

SH - SL H

308.8 - 180 970.3

Chart CG-3.Percentage of flash steam formed when discharging condensate to reduced pressure.

Chart CG-4.Volume of flash steam formed when one cubic foot of condensate is discharged to atmospheric pressure.

Steam Tables

CG-4




CG-5

1 lb waterat 70F,0 psig

1 lb waterat 338F,100 psig

1 lb steamat 338F,100 psig

+ 270 Btu = + 880 Btu =

+ 142 Btu =

1 lb steamat 212F

+ 970 Btu =

1 lb waterat 212F

1 lb waterat 70F

Steam is an invisible gas generated by adding heat energy to water in a boiler. Enough energy must be added to raise the temperature of the water to the boiling point. Then additional energywithout any further increase in tem-peraturechanges the water to steam.

Steam is a very effi cient and easily controlled heat transfer medium. It is most often used for transporting energy from a central location (the boiler) to any number of locations in the plant where it is used to heat air, water or process applications.

As noted, additional Btu are required to make boiling water change to steam. These Btu are not lost but stored in the steam ready to be released to heat air, cook tomatoes, press pants or dry a roll of paper.

The heat required to change boiling water into steam is called the heat of vaporization or latent heat. The quantity is different for every pressure/temperature combination, as shown in the steam tables.

Steam at WorkHow the Heat of Steam Is UtilizedHeat fl ows from a higher temperature level to a lower temperature level in a process known as heat transfer. Starting in the combustion chamber of the boiler, heat fl ows through the boiler tubes to the water. When the higher pressure in the boiler pushes steam out, it heats the pipes of the distribution system. Heat fl ows from the steam through the walls of the pipes into the cooler surrounding air. This heat transfer changes some of the steam back into water. Thats why distribution lines are usually insulated to minimize this wasteful and undesirable heat transfer.

When steam reaches the heat exchangers in the system, the story is different. Here the transfer of heat from the steam is desirable. Heat fl ows to the air in an air heater, to the water in a water heater or to food in a cooking kettle. Nothing should interfere with this heat transfer.

Condensate DrainageWhy Its NecessaryCondensate is the by-product of heat transfer in a steam system. It forms in the distribution system due to unavoidable radiation. It also forms in heating and process equipment as a result of desirable heat transfer from the steam to the substance heated. Once the steam has condensed and given up its valuable latent heat, the hot condensate must be removed immediately. Although the available heat in a pound of condensate is negligible as compared to a pound of steam, condensate is still valuable hot water and should be returned to the boiler.

Definitions The Btu. A BtuBritish thermal unitis the amount of

heat energy required to raise the temperature of one pound of cold water by 1F. Or, a Btu is the amount of heat energy given off by one pound of water in cooling, say, from 70F to 69F.

Temperature. The degree of hotness with no implication of the amount of heat energy available.

Heat. A measure of energy available with no implication of temperature. To illustrate, the one Btu that raises one pound of water from 39F to 40F could come from the surrounding air at a temperature of 70F or from a fl ame at a temperature of 1,000F.

Figure CG-1. These drawings show how much heat is required to generate one pound of steam at atmo-spheric pressure. Note that it takes 1 Btu for every 1 increase in temperature up to the boiling point, but that it takes more Btu to change water at 212F to steam at 212F.

Figure CG-2. These drawings show how much heat is required to generate one pound of steam at 100 pounds per square inch pressure. Note the extra heat and higher temperature required to make water boil at 100 pounds pressure than at atmospheric pressure. Note, too, the lesser amount of heat required to change water to steam at the higher temperature.

Condensate Steam

10

SteamBasic Concepts




Vent

TrapTrap

Trap

Trap

Trap

Trap

100 psig337.9F

50.3 psig297.97F

PRV

A B

FLUID TO BE HEATED

METAL

SCALE

DIRTWATER

NON-CONDENSABLEGASES

STEAM

COIL PIPE CUTAWAY

The need to drain the distribution system. Condensate lying in the bottom of steam lines can be the cause of one kind of water hammer. Steam traveling at up to 100 miles per hour makes waves as it passes over this condensate Fig. CG-4). If enough condensate forms, high-speed steam pushes it along, creating a dangerous slug that grows larger and larger as it picks up liquid in front of it. Anything that changes the directionpipe fi ttings, regulating valves, tees, elbows, blind fl angescan be destroyed. In addition to damage from this battering ram, high-velocity water may erode fi ttings by chipping away at metal surfaces.

The need to drain the heat transfer unit. When steam comes in contact with condensate cooled below the temper-ature of steam, it can produce another kind of water hammer known as thermal shock. Steam occupies a much greater volume than condensate, and when it collapses suddenly, it can send shock waves throughout the system. This form of water hammer can damage equipment, and it signals that condensate is not being drained from the system.Obviously, condensate in the heat transfer unit takes up space and reduces the physical size and capacity of the equipment. Removing it quickly keeps the unit full of steam (Fig. CG-5). As steam condenses, it forms a fi lm of water on the inside of the heat exchanger. Non-condensable gases do not change into liquid and fl ow away by gravity. Instead, they accumulate as a thin fi lm on the surface of the heat exchangeralong with dirt and scale. All are potential barriers to heat transfer (Fig. CG-3).

The need to remove air and CO2. Air is always present during equipment start-up and in the boiler feedwater. Feedwater may also contain dissolved carbonates, which release carbon dioxide gas. The steam velocity pushes the gases to the walls of the heat exchangers, where they may block heat transfer. This compounds the condensate drainage problem, because these gases must be removed along with the condensate.

Figure CG-3. Potential barriers to heat transfer: steam heat and temperature must penetrate these potential barriers to do their work.

Figure CG-6. Note that heat radiation from the distribution system causes condensate to form and, therefore, requires steam traps at natural low points or ahead of control valves. In the heat exchangers, traps perform the vital function of removing the condensate before it becomes a barrier to heat transfer. Hot condensate is returned through the traps to the boiler for reuse.

Figure CG-5. Coil half full of condensate cant work at full capacity.

Figure CG-4. Condensate allowed to collect in pipes or tubes is blown into waves by steam passing over it until it blocks steam flow at point A. Condensate in area B causes a pressure differential that allows steam pressure to push the slug of condensate along like a battering ram.

Condensate Steam Vapor

11

SteamBasic Concepts

CG-6




450

425

400

375

350

325

300

275

250

225

200

150

100

300 250 200 150 100 75 50 25 0 100 90

80 70

60

50 40

30 2

0 10

0

100 90 8

0 70

60 50

40 30

20 10

0

PERCENT

AIR BY VO

LUME%

PRESSUREPSIG300 250 200 150 100 75 50 25 0

0

450

425400

375

350

325

300

275250

225

200

150

100

0

TE

MP

ER

AT

UR

E

F

Effect of Air on Steam TemperatureWhen air and other gases enter the steam system, they consume part of the volume that steam would otherwise occupy. The temperature of the air/steam mixture falls below that of pure steam. Figure CG-7 explains the effect of air in steam lines. Table CG-2 and Chart CG-5 show the vari-ous temperature reductions caused by air at various per-centages and pressures.

Effect of Air on Heat TransferThe normal fl ow of steam toward the heat exchanger sur-face carries air and other gases with it. Since they do not condense and drain by gravity, these non-condensable gases set up a barrier between the steam and the heat exchanger surface. The excellent insulating properties of air reduce heat transfer. In fact, under certain conditions as little as 1/2 of 1% by volume of air in steam can reduce heat transfer effi ciency by 50% (Fig. CG-8).

Table CG-2. Temperature Reduction Caused by Air

Pressure (psig)

Temp. of Steam, No Air Present (F)

Temp. of Steam Mixed With Various Percentages of Air (by Volume) (F)

10% 20% 30%10.3 240.1 234.3 228.0 220.925.3 267.3 261.0 254.1 246.450.3 298.0 291.0 283.5 275.175.3 320.3 312.9 304.8 295.9100.3 338.1 330.3 321.8 312.4

When non-condensable gases (primarily air) continue to accumulate and are not removed, they may gradually fi ll the heat exchanger with gases and stop the fl ow of steam altogether. The unit is then air bound.

CorrosionTwo primary causes of scale and corrosion are carbon dioxide (CO2) and oxygen. CO2 enters the system as carbonates dissolved in feedwater and, when mixed with cooled condensate, creates carbonic acid. Extremely corrosive, carbonic acid can eat through piping and heat exchangers (Fig. CG-9). Oxygen enters the system as gas dissolved in the cold feedwater. It aggravates the action of carbonic acid, speeding corrosion and pitting iron and steel surfaces (Fig. CG-10).

Eliminating the UndesirablesTo summarize, traps must drain condensate because it can reduce heat transfer and cause water hammer. Traps should evacuate air and other non-condensable gases because they can reduce heat transfer by reducing steam temperature and insulating the system. They can also foster destructive corrosion. Its essential to remove condensate, air and CO2 as quickly and completely as possible. A steam trap, which is simply an automatic valve that opens for condensate, air and CO2 and closes for steam, does this job. For economic reasons, the steam trap should do its work for long periods with minimum attention.

Chart CG-5. Air Steam MixtureTemperature reduction caused by various percentages of air at differing pres-sures. This chart determines the percentage of air with known pressure and tem-perature by determining the point of intersection between pressure, temperature and percentage of air by volume. As an example, assume system pressure of 250 psig with a temperature at the heat exchanger of 375F. From the chart, it is deter-mined that there is 30% air by volume in the steam.

Figure CG-7. Chamber containing air and steam delivers only the heat of the partial pressure of the steam, not the total pressure.

Steam chamber 100% steamTotal pressure 100 psia

Steam pressure 100 psiaSteam temperature 327.8F

Steam chamber 90% steam and 10% airTotal pressure 100 psiaSteam pressure 90 psia

Steam temperature 320.3F

SteamBasic Concepts

CG-7




What the Steam Trap Must DoThe job of the steam trap is to get condensate, air and CO2 out of the system as quickly as they accumulate. In addition, for overall effi ciency and economy, the trap must also provide:

1. Minimal steam loss. Table CG-3 shows how costly unattended steam leaks can be.

2. Long life and dependable service. Rapid wear of parts quickly brings a trap to the point of undependabil-ity. An effi cient trap saves money by minimizing trap testing, repair, cleaning, downtime and associated losses.

3. Corrosion resistance. Working trap parts should be corrosion-resistant in order to combat the damaging effects of acidic or oxygen-laden condensate.

4. Air venting. Air can be present in steam at any time and especially on start-up. Air must be vented for effi cient heat transfer and to prevent system binding.

5. CO2 venting. Venting CO2 at steam temperature will prevent the formation of carbonic acid. Therefore, the steam trap must function at or near steam temperature since CO2 dissolves in condensate that has cooled below steam temperature.

6. Operation against back pressure. Pressurized return lines can occur both by design and unintentionally. A steam trap should be able to operate against the actual

back pressure in its return system.

7. Freedom from dirt problems. Dirt is an ever-present concern since traps are located at low points in the steam system. Condensate picks up dirt and scale in the piping, and solids may carry over from the boiler. Even particles passing through strainer screens are erosive and, therefore, the steam trap must be able to operate in the presence of dirt.

A trap delivering anything less than all these desirable operating/design features will reduce the effi ciency of the system and increase costs. When a trap delivers all these features the system can achieve:

1. Fast heat-up of heat transfer equipment2. Maximum equipment temperature for enhanced steam heat transfer3. Maximum equipment capacity4. Maximum fuel economy5. Reduced labor per unit of output6. Minimum maintenance and a long trouble-free service life

Sometimes an application may demand a trap without these design features, but in the vast majority of applica-tions the trap which meets all the requirements will deliver the best results.

Figure CG-9. CO2 gas combines with condensate allowed to cool below steam temperature to form carbonic acid, which corrodes pipes and heat transfer units. Note groove eaten away in the pipe illustrated.

Figure CG-8. Steam condensing in a heat transfer unit moves air to the heat transfer surface, where it collects or plates out to form effective insulation.

Figure CG-10. Oxygen in the system speeds corrosion (oxidation) of pipes, causing pitting such as shown here. Figs. CG-9 and CG-10 courtesy of Dearborn Chemical Company.

Condensate Steam

SteamBasic Concepts

Table CG-3. Cost of Various Sized Steam Leaks at 100 psi (Assuming steam costs $10.00/1,000 lbs)

Size of Orifice Lbs Steam Wasted Per Month Total Cost Per Month

(USD)Total Cost Per Year

(USD

1/2" 12, 7 mm 553,000 $5,530.00 $66,360.007/16" 11, 2 mm 423,500 4,235.00 50,820.003/8" 9, 5 mm 311,000 3,110.00 37,320.005/16" 7, 9 mm 216,000 2,160.00 25,920.001/4" 6, 4 mm 138,000 1,380.00 16,560.003/16" 4, 8 mm 78,000 780.00 9,360.001/8" 3, 2 mm 34,500 345.00 4,140.00

The steam loss values assume typical condensate load for drip trap applications.Armstrong methodology for steam trap management and condensate return is sanctioned by the Clean DevelopmentMechanism of the United Nations Framework Convention on Climate Change.

CG-8




Valve Wide Open

Flow Here Picks Up Dirt

The Armstrong inverted submerged bucket steam trap is a mechanical trap that operates on the difference in density between steam and water. See Fig. CG-11. Steam entering the inverted submerged bucket causes the bucket to fl oat and close the discharge valve. Condensate entering the trap changes the bucket to a weight that sinks and opens the trap valve to discharge the condensate. Unlike other mechanical traps, the inverted bucket also vents air and carbon dioxide continuously at steam temperature.

This simple principle of condensate removal was introduced by Armstrong in 1911. Years of improvement in materials and manufacturing have made todays Armstrong inverted bucket traps virtually unmatched in operating effi ciency, dependability and long life.

Long, Energy-Efficient Service LifeAt the heart of the Armstrong inverted bucket trap is a unique leverage system that multiplies the force provided by the bucket to open the valve against pressure. There are no fi xed pivots to wear or create friction. It is designed to open the discharge orifi ce for maximum capacity. Since the buck-et is open at the bottom, it is resistant to damage from water hammer. Wearing points are heavily reinforced for long life.

An Armstrong inverted bucket trap can continue to conserve energy even in the presence of wear. Gradual wear slightly increases the diameter of the seat and alters the shape and diameter of the ball valve. But as this occurs, the ball merely seats itself deeperpreserving a tight seal.

Reliable OperationThe Armstrong inverted bucket trap owes much of its reliability to a design that makes it virtually free of dirt problems. Note that the valve and seat are at the top of the trap. The larger particles of dirt fall to the bottom, where they are pulverized under the up-and-down action of the bucket. Since the valve of an inverted bucket is either closed or fully open, there is free passage of dirt particles. In addition, the swift fl ow of condensate from under the buckets edge creates a unique self-scrubbing action that sweeps dirt out of the trap. The inverted bucket has only two moving partsthe valve lever assembly and the bucket. That means no fi xed points, no complicated linkagesnothing to stick, bind or clog.

Corrosion-Resistant PartsThe valve and seat of Armstrong inverted bucket traps are high chrome stainless steel, ground and lapped. All other working parts are wear- and corrosion-resistant stainless steel.

Operation Against Back PressureHigh pressure in the discharge line simply reduces the differential across the valve. As back pressure approaches that of inlet pressure, discharge becomes continuous just as it does on the very low pressure differentials.

Back pressure has no adverse effect on inverted bucket trap operation other than capacity reduction caused by the low differential. There is simply less force required by the bucket to pull the valve open, cycling the trap.

1. Steam trap is installed in drain line between steam-heated unit and condensate return header. On start-up, bucket is down and valve is wide open. As initial flood of condensate enters the trap and flows under bottom of bucket, it fills trap body and completely submerges bucket. Condensate then discharges through wide-open valve to return header.

2. Steam also enters trap under bottom of bucket, where it rises and collects at top, imparting buoyancy. Bucket then rises and lifts valve toward its seat until valve is snapped tightly shut. Air and carbon dioxide continually pass through bucket vent and collect at top of trap. Any steam passing through vent is condensed by radiation from trap.

Condensate Steam Air Flashing Condensate

Figure CG-11. Operation of the Inverted Bucket Steam Trap (at pressures close to maximum)

Valve Closed

The Inverted Bucket Steam Trap

CG-9




Valve Wide Open

Self Scrubbing

Flow

Valve Closed

3. As the entering condensate starts to fill the bucket, the bucket begins to exert a pull on the lever. As the condensate continues to rise, more force is exerted until there is enough to open the valve against the differential pressure.

4. As the valve starts to open, the pressure force across the valve is reduced. The bucket then sinks rapidly and fully opens the valve. Accumulated air is discharged first, followed by condensate. The flow under the bottom of the bucket picks up dirt and sweeps it out of the trap. Discharge continues until more steam floats the bucket, and the cycle repeats.

Types of Armstrong Inverted Bucket Traps Available to Meet Specific RequirementsThe availability of inverted bucket traps in different body materials, piping confi gurations and other variables permits fl exibility in applying the right trap to meet specifi c needs. See Table CG-4.

1. All-Stainless Steel Traps. Sealed, tamper-proof stain-less steel bodies enable these traps to withstand freeze-ups without damage. They may be installed on tracer lines, outdoor drips and other services subject to freezing. For pressures to 650 psig and temperatures to 800F.

2. Cast Iron Traps. Standard inverted bucket traps for general service at pressures to 250 psig and temperatures to 450F. Offered with side connections, side connections with inte-gral strainers and bottom inlettop outlet connections.

3. Forged Steel Traps. Standard inverted bucket traps for high pressure, high temperature services (including superheated steam) to 2,700 psig at 1,050F.

4. Cast Stainless Steel Traps. Standard inverted bucket traps for high capacity, corrosive service. Repairable. For pressures to 700 psig and temperatures to 506F.

The Inverted Bucket Steam Trap

Table CG-4. Typical Design Parameters for Inverted Bucket Traps

Body and Cap Materials Cast Iron Stainless Steel Forged Steel Cast Steel Cast Stainless Steel

Connections 1/2" thru 2-1/2" 3/8" thru 1" 1/2" thru 2" 1/2" thru 1" 1/2" thru 2"

Type Connections Screwed Screwed, Socketweld Screwed, Socketweld or Flanged Screwed, Socketweld

or Flanged Screwed, Socketweld

or Flanged

Operating Pressure (psig) 0 thru 250 0 thru 650 0 thru 2,700 0 thru 600 0 thru 700

Capacity (lbs/hr) To 20,000 To 4,400 To 20,000 To 4,400 To 20,000

CG-10




The fl oat and thermostatic trap is a mechanical trap that operates on both density and temperature principles. The fl oat valve operates on the density principle: A lever con-nects the ball fl oat to the valve and seat. Once condensate reaches a certain level in the trap the fl oat rises, opening the orifi ce and draining condensate. A water seal formed by the condensate prevents live steam loss.

Since the discharge valve is under water, it is not capable of venting air and non-condensables. When the accumulation of air and non-condensable gases causes a signifi cant tem-perature drop, a thermostatic air vent in the top of the trap discharges it. The thermostatic vent opens at a temperature a few degrees below saturation so its able to handle a large volume of airthrough an entirely separate orifi cebut at a slightly reduced temperature.

Armstrong F&T traps provide high air-venting capacity, respond immediately to condensate and are suitable for both industrial and HVAC applications.

Reliable Operation on Modulating Steam PressureModulating steam pressure means that the pressure in the heat exchange unit being drained can vary anywhere from the maximum steam supply pressure down to vacuum under certain conditions. Thus, under conditions of zero pressure, only the force of gravity is available to push condensate through a steam trap. Substantial amounts of air may also be liberated under these conditions of low steam pressure. The effi cient operation of the F&T trap meets all of these specialized requirements.

High Back Pressure OperationBack pressure has no adverse effect on fl oat and thermostatic trap operation other than capacity reduction due to low differential. The trap will not fail to close and will not blow steam due to the high back pressure.

Table CG-5. Typical Design Parameters for Float and Thermostatic TrapsBody and Cap Materials Cast Iron Cast SteelConnections 1/2" thru 3" 1/2" thru 3"

Type Connections Screwed or Flanged Screwed, Socketweld or Flanged

Operating Pressure (psig) 0 thru 250 0 thru 465

Capacity (lbs/hr) To 208,000 To 280,000

Figure CG-12. Operation of the F&T Steam Trap

1. On start-up, low system pressure forces air out through the thermostatic air vent. A high condensate load normally follows air venting and lifts the float, which opens the main valve. The remaining air continues to discharge through the open vent.

2. When steam reaches the trap, the thermostatic air vent closes in response to higher temperature. Condensate continues to flow through the main valve, which is positioned by the float to discharge condensate at the same rate that it flows to the trap.

3. As air accumulates in the trap, the temperature drops below that of saturated steam. The balanced pressure thermostat-ic air vent opens and discharges air.

NOTE: These operational schematics of the F&T trap do not represent actual trap configuration.

Condensate Steam Air

The Float and Thermostatic Steam Trap

CG-11




The controlled disc steam trap is a time-delayed device that oper-ates on the velocity principle. It contains only one moving part, the disc itself. Because it is very lightweight and compact, the CD trap meets the needs of many applications where space is limited. In addition to the disc traps simplicity and small size, it also offers advantages such as resistance to hydraulic shock, the complete discharge of all condensate when open and intermittent operation for a steady purging action.

Operation of controlled disc traps depends on the changes in pressures in the chamber where the disc operates. The Armstrong CD trap will be open as long as cold condensate is fl owing. When steam or fl ash steam reaches the inlet orifi ce, velocity of fl ow increases, pulling the disc toward the seat. Increasing pressure in the control chamber snaps the disc closed. The subsequent pressure reduction, necessary for the trap to open, is controlled by the heating chamber in the cap and a fi nite machined bleed groove in the disc. Once the system is up to temperature, the bleed groove controls the trap cycle rate.

Unique Heating ChamberThe unique heating chamber in Armstrongs controlled disc traps surrounds the disc body and control chamber. A controlled bleed from the chamber to the trap outlet controls the cycle rate. That means that the trap designnot ambient conditionscontrols the cycle rate. Without this controlling feature, rain, snow and cold ambient conditions would upset the cycle rate of the trap.

Table CG-6. Typical Design Parameters for Controlled Disc TrapsBody and Cap Materials SteelConnections 3/8" thru 1"Type Connections Screwed, Socketweld or FlangedOperating Pressure (psig) 10 thru 600Capacity (lbs/hr) To 2,850

1. On start-up, condensate and air entering the trap pass through the heating chamber, around the control chamber and through the inlet orifice. This flow lifts the disc off the inlet orifice, and the condensate flows through to the outlet passages.

2. Steam enters through the inlet passage and flows under the control disc. The flow velocity across the face of the control disc increases, creating a low pressure that pulls the disc toward the seat.

3. The disc closes against two concentric faces of the seat, closing off the inlet passage and also trapping steam and condensate above the disc. There is a controlled bleeding of steam from the control chamber; flashing condensate helps main-tain the pressure in the control chamber. When the pressure above the disc is reduced, the incoming pressure lifts the disc off the seat. If condensate is present, it will be discharged, and the cycle repeats.

Figure CG-13. Design and Operation of Controlled Disc Traps

Heating ChamberControl Chamber

Control Disc

Inlet Passage

Outlet Passages

High Velocity FlowSeat

Control Chamber

Disc is held against two concentric faces of seat

Condensate Steam Air Condensate and Steam Mixture

1. On start-up, the trap is cold, so the elements are flat and the valve is wide open, which results in air and condensate being easily removed from the system by working pressure.

2. With increasing temperature of the condensate, the bimetallic elements will start to expand and flex.

3. When set temperature is reached, the force of the elements is high enough to close the valve completely against the system pressure working on the valve.

Bimetallic steam traps have the ability to handle large start-up loads. As the trap increases in temperature, its stacked nickel-chrome bimetallic elements start to expand, allowing for tight shutoff as steam reaches the trap, thus preventing steam loss. In addition to its light weight and compact size, it offers resistance to water hammer. Titanium valve and seat on high-pressure bimetallic traps ensure extremely long service life in the harsh environment of superheated steam systems.

The Bimetallic Steam Trap

Figure CG-14. Design and Operation of Bimetallic Steam Traps Condensate Steam Air Flashing Steam

The Controlled Disc Steam Trap

Table CG-7. Typical Design Parameters for Bimetallic TrapsBody and Cap Materials Carbon Steel Stainless SteelConnection Sizes 1/2", 3/4", 1"

Type Connections Screwed,

Socketweld, Flanged

Screwed, NPT, BSPT, Socketweld, Buttweld, Flanged

Operating psig 0 - 250 200 - 900Cold Water Capacity lb/hr up to 11,000

CG-12




Armstrong thermostatic steam traps are available with balanced pressure bellows or wafer-type elements and are constructed in a wide variety of materials, including stainless steel, carbon steel and bronze. These traps are used on applications with very light condensate loads.

Thermostatic OperationThermostatic steam traps operate on the difference in temperature between steam and cooled condensate and air. Steam increases the pressure inside the thermostatic element, causing the trap to close. As condensate and non-condensable gases back up in the cooling leg, the temperature begins to drop, and the thermostatic element contracts and opens the valve. The amount of condensate backed up ahead of the trap depends on the load conditions, steam pressure and size of the piping. It is important to note that an accumulation of non-condensable gases can occur behind the condensate backup.

Table CG-8. Design Parameters for Thermostatic TrapsBalanced Pressure

Bellows Balanced Pressure Wafer

Body and Cap Materials

Stainless Steel Bronze

Stainless Steel

Carbon Steel Bronze

Connections 1/2", 3/4" 1/2", 3/4" 1/4" thru 1" 1/2", 3/4" 1/2", 3/4", 1"

Type Connections

Screwed, Socketweld

NPT Straight,

Angle

Screwed, Socketweld

Screwed, Socketweld

NPT Straight,

Angle

Operating Pressure (psig)

0 - 300 0 - 50 0 - 400 0 - 600 0 - 65

Capacity (lbs/hr) To 3,450 To 1,600 To 70 To 85 To 960

NOTE: Thermostatic traps can also be used for venting air from a steam system. When air collects, the tem-perature drops and the thermostatic air vent automatically discharges the air at slightly below steam temperature throughout the entire operating pressure range.

Figure CG-15. Operation of the Thermostatic Steam Trap

1. On start-up, condensate and air are pushed ahead of the steam directly through the trap. The thermostatic bellows element is fully contracted, and the valve remains wide open until steam approaches the trap.

2. As the temperature inside the trap increases, it quickly heats the charged bellows element, increasing the vapor pressure inside. When pressure inside the element becomes balanced with system pressure in the trap body, the spring effect of the bellows causes the element to expand, closing the valve. When temperature in the trap drops a few degrees below saturated steam temperature, imbalanced pres-sure contracts the bellows, opening the valve.

Figure CG-16. Operation of Thermostatic Wafer

Balanced Pressure Thermostatic Wafer operation is very similar to bal-anced pressure bellows described in Fig. CG-15. The wafer is partially filled with a liquid. As the temperature inside the trap increases, it heats the charged wafer, increasing the vapor pressure inside. When the pressure inside the wafer exceeds the surrounding steam pressure, the wafer membrane is forced down on the valve seat, and the trap is closed. A temperature drop caused by condensate or non-con-densable gases cools and reduces the pressure inside the wafer, allowing the wafer to uncover the seat.

Steam Condensate Condensate and Air

Alcohol Vapor Wafer Alcohol

Liquid

Alcohol Chamber

Bulkhead

The Thermostatic Steam Trap

CG-13




Secondary Steam

Bucket

Inlet

Condensate Discharge Valve

Manual Metering Valve

Outlet

Condensate

Live and Flash Steam

Condensate and Secondary Steam

Dot

ted

Line

s In

dica

te F

ield

Pip

ing

Armstrong automatic differential condensate controllers (DC) are designed to function on applications where condensate must be lifted from a drain point or in gravity drainage applications where increased velocity will aid in drainage.

Lifting condensate from the drain pointoften referred to as syphon drainagereduces the pressure of condensate, causing a portion of it to fl ash into steam. Since ordinary steam traps are unable to distinguish fl ash steam and live steam, they close and impede drainage.

Increased velocity with gravity drainage will aid in drawing the condensate and air to the DC. An internal steam by-pass controlled by a manual metering valve causes this increased velocity. Therefore, the condensate controller automatically vents the by-pass or secondary steam. This is then collect-ed for use in other heat exchangers or discharged to the condensate return line.

Capacity considerations for draining equipment vary greatly according to the application. However, a single condensate controller provides suffi cient capacity for most applications.

Condensate Controller OperationCondensate, air and steam (live and fl ash) enter through the controller inlet. At this point fl ash steam and air are automat-ically separated from the condensate. Then they divert into the integral by-pass at a controlled rate, forming secondary steam (See Fig. CG-18).

The valve is adjustable so it matches the amount of fl ash present under full capacity operation or to meet the veloc-ity requirements of the system. The condensate discharges through a separate orifi ce controlled by the inverted bucket.

Because of the dual orifi ce design, there is a preset controlled pressure differential for the secondary steam system, while maximum pressure differential is available to discharge the condensate.

Table CG-9. Typical Design Parameters for the Automatic Differential Condensate ControllerBody and Cap Materials Cast Iron SteelConnections 1/2" thru 2" 1" thru 2"Type Connections Screwed ScrewedOperating Pressure (psig) 0 thru 250 0 thru 650Capacity (lbs/hr) To 20,000 To 20,000Figure CG-17.

For the most efficient use of steam energy, Armstrong recommends this piping arrangement when secondary steam is collected and reused in heat transfer equipment.

Figure CG-18. Condensate Controller Operation

Piping arrangement when flash steam and non-condensables are to be removed and discharged directly to the conden-sate return line.

To Secondary Steam Header

Condensate Return

DC

DC

Condensate Return

The Automatic Differential Condensate Controller

CG-14




10"-12"

6"

To obtain the full benefi ts from the traps described in the preceding section, it is essential to select traps of the correct size and pressure for a given job and to install and maintain them properly. One of the purposes of this section is to supply the information to make that possible. Actual installation and operation of steam trapping equip-ment should be performed only by experienced personnel. Selection or installation should always be accompanied by competent technical assistance or advice. This sec-tion should never be used as a substitute for such techni-cal advice or assistance. We encourage you to contact Armstrong or its local representative for further details.

Basic ConsiderationsUnit trapping is the use of a separate steam trap on each steam-condensing unit including, whenever possible, each separate chest or coil of a single machine. The discussion under the Short Circuiting heading explains the why of unit trapping versus group trapping.

Rely on experience. Select traps with the aid of experience either yours, the know-how of your Armstrong Representative or what others have learned in trapping similar equipment.

Do-it-yourself sizing. Do-it-yourself sizing is simple with the aid of Steam-A-ware, Armstrongs sizing and selection software program, which can be downloaded at armstronginternational.com.

Even without this computer program, you can easily size steam traps when you know or can calculate: 1. Condensate loads in lbs/hr 2. The safety factor to use 3. Pressure differential 4. Maximum allowable pressure

1. Condensate load. Each How To portion of this section contains formulas and useful information on steam condensing rates and proper sizing procedures.

2. Safety factor or experience factor to use. Users have found that they must generally use a safety factor in siz-ing steam traps. For example, a coil condensing 500 lbs/hr might require a trap that could handle up to 1,500 for best overall performance. This 3:1 safety factor takes care of varying condensate rates, occasional drops in pressure differential and system design factors.

Safety factors will vary from a low of 1.5:1 to a high of 10:1. The safety factors in this book are based on years of user experience.

Confi guration affects safety factor. More important than ordinary load and pressure changes is the design of the steam-heated unit itself. Refer to Figs. CG-21, CG-22 and CG-23 showing three condensing units each producing 500 pounds of condensate per hour, but with safety factors of 2:1, 3:1 and 8:1.

Figure CG-19. Two steam-consuming units drained by a single trap, referred to as group trapping, may result in short circuiting.

Figure CG-20. Short circuiting is impos-sible when each unit is drained by its own trap. Higher efficiency is assured.

Short CircuitingIf a single trap connects more than one drain point, condensate and air from one or more of the units may fail to reach the trap. Any difference in condensing rates will result in a difference in the steam pressure drop. A pressure drop difference too small to register on a pressure gauge is enough to let steam from the higher pressure unit block the flow of air or condensate from the lower pressure unit. The net result is reduced heating, output and fuel waste (see Figs. CG-19 and CG-20).

Figure CG-21. Continuous coil, constant pressure gravity flow to trap. 500 lbs/hr of condensate from a single copper coil at 30 psig. Gravity drainage to trap. Volume of steam space very small. 2:1 safety factor.

Figure CG-22. Multiple pipes, modu-lated pressure gravity flow to trap. 500 lbs/hr of condensate from unit heater at 80 psig. Multiple tubes create minor short-circuiting hazard. Use 3:1 safety factor at 40 psig.

Figure CG-23. Large cylinder, syphon drained. 500 lbs/hr from a 4' diameter, 10' long cylinder dryer with 115 cu ft of space at 30 psig. The safety factor is 3:1 with a DC and 8:1 with an IB.

Identical Condensing Rates, Identical Pressures With Differing Safety Factors

Condensate Steam

Wrong Right

Trap Selection

CG-15




9'

8'

7'

6'

5'

4'

3'

2'

1'

4 psi

3 psi

2 psi

1 psi

Water Seal

Trap

Lift in feet

Pressuredrop overwater sealto lift coldcondensate

Steam Main

Economical steam trap/orifi ce selection. While an adequate safety factor is needed for best performance, too large a factor causes problems. In addition to higher costs for the trap and its installation, a needlessly oversized trap wears out more quickly. And in the event of a trap failure, an oversized trap loses more steam, which can cause water hammer and high back pressure in the return system.

3. Pressure differential. Maximum differential is thedifference between boiler or steam main pressure or the downstream pressure of a PRV and return line pressure. See Fig. CG-24. The trap must be able to open against this pressure differential.

NOTE: Because of fl ashing condensate in the return lines, dont assume a decrease in pressure differential due to static head when elevating.

Operating differential. When the plant is operating at capacity, the steam pressure at the trap inlet may be lower than steam main pressure. And the pressure in the conden-sate return header may go above atmospheric.

If the operating differential is at least 80% of the maxi-mum differential, it is safe to use maximum differential in selecting traps.

Modulated control

Documents

Armstrong Educational Handbook and All Products Catalog